Solution K10216390
Monday, June 3, 2019 7:09:39 PM CEST

** SOLUTION **
Title

** Tech Tip ** - TT-019-2016 Automated Manual Transmission ( AMT ) Bearing And
Gear Shaft Inspection

Mack Models
AN - Anthem , CHU - Pinnacle, Axle back , CXU - Pinnacle, Axle front , GR - Granite

Mack Model

, GU - Granite , PI - Pinnacle , TD - Titan

Volvo Models
VNL , VNM , VNR , VNX , VAH , VHD , VT

Volvo Model

Engine family
Engine family

11L Engine , 13L Engine , 16L Engine , MP7 , MP8 , MP10

Transmission
Transmission

AMT-F With Crawler Gears , AMT-F Without Crawler Gears , AMT-C , AMT-D , A
MT-F , AMT-C , AMT-D , AMT-F With Crawler Gears , AMT-F Without Crawler
Gears

** SOLUTION **
Cause

The customer has a driveability complaint for the vehicle bucking, slipping, or engine
surging when in reverse.

Soluti

Codes associated with this complaint:

on
P1071- Split Engagement System, FTB 96 Unintentional disengagement of direct split
P1057- Main Shaft Speed Sensor, FTB 21 Data valid but below operational range

Most probable cause:

Loss of main shaft pre-load from a spigot bearing failure

Recommended Actions: Review pictures and perform instructions below

Towing Related Failure (Image 1)

Towing Related Failure (Image 2)

Spalled bearing failure (Image 3)

Spalled bearing race (Image 4)

Additional checks:
Reviewing DTC readout can be helpful in determining spalled vs. towing damaged spigot bearing. Main shaft
speed codes prior to any towing event can indicate that the loss of main shaft pre-load may have begun before
the truck was towed to the shop. This means that the bearing started to spall before the unit was towed
improperly.

Spalled Bearing Failure (Image 5)

Spalled Bearing Race (Image 6)

These images (5 & 6) represent a failure that went ignored for some time.

While the main shaft does not have evidence of heat as in the towing example (image 1), there are additional
parts that have been affected:

• Contact with the main shaft nut
• Rollers missing and race worn down
• Oil distribution tube twisted off and closed
• P1 bearing damaged
• Split synchro ring broken

Clues that this may have been a spalled, or otherwise damaged, spigot bearing is:

1. The ridge in the input shaft. This is similar to what is seen in the spalled spigot bearing failure image 3.
2. The DTC readout, as in the example below. The vehicle clock is incorrect however you can assume that the
"Last Occurrence" has to be close to the readout day. In this example you can see that there had been main
shaft codes for ~2 mo and split shift codes for ~3mo

Code Description:

P1071- Split Engagement System, FTB 96 (FMI 1) Unintentional disengagement of direct split

Fault Condition:

High split jumps out
The split cylinder valves are inactive

Possible Symptom:

Yellow lamp is illuminated
Loss of torque

Possible Cause:

N/A

P1057 (PID 160) Main Shaft Speed Sensor, FTB 21 (FMI 1) Data valid but below operational range

Fault Condition:

The sensor signal is within normal range and, the main shaft speed differs from both the value of the
countershaft speed and the vehicle speed received from the vehicle ECU. The following conditions must be
fulfilled for a time of 2.0 seconds in order to activate:

A gear (not neutral) is engaged in the transmission
The value of the input shaft speed calculated from the main shaft speed sensor (SESM) is more than
300 rpm
The value of the input shaft speed calculated from the counter shaft speed sensor (SESC) is more than
300 rpm

Possible Symptom:

Yellow lamp is illuminated
Slow gear changes
Rough gear changes

Possible Cause:

N/A

Solution visibility

Dealer distribution

Function(s)/component(s) affected
Function affected

TT

, engagement , Input Shaft , Main Shaft , Front Housing (Gearbox)

Function Group
Function Group

431 gearbox, manual

Customer effect
Main customer effect

judder , slipping

Fault Codes And Error Codes
OBDII Diagnostic Trouble
Codes (P, U, B Format)

P1057 , P1071

Conditions
Vehicle operating mode

acceleration , in reverse , engagement , during engagement

Administration
Author

ut01793

Last modified by

RU4469V

Creation date

10-11-2016 21:11

Date of last update

30-05-2019 16:05

Status

Published